The dimension of 15.6"laptop is smaller than the dimension 382 x 253 x 32mm and can use 15.6" bag, but if you also pack power supply, mouse inside or the 15.6"laptop with bigger size, you should choose 17" bag.Measurements and Sizes Exterior: 16.1"(l) x 11.6"(w) x 1"(h) Interior: 15.4"(l) x 10.8"(w) x 0.9"(h)

Note ：This case is water resistant but not water proof, and You can expect the water to stay on the surface for a while until it actually soaks through, but don't try to soak it in water